I've stayed at a lot of hotels in Moab and we like the La Quinta the best.
With the AAA discount (they never ask for a card even if you don't have it) their rates work out to be pretty good.
It's a really nice hotel, clean, big rooms, great breakfast, and lots of parking.
If you sign up for the returns program, which is free, you get a free nights stay after your first 8 nights, and then I think it goes to a free night every 5.
Prior to La Quinta, I liked Aarchway Inn, but they recently changed management and their rates have gone way up. Service has gone down too, I wasn't too impressed at all last time I stayed there, but it was really nice 2-3 years ago.